1. Field of the Invention
This invention relates to an internal combustion engine for a vehicle which includes an oil cooler, an oil filter and an electric motor. More particularly, to an arrangement and an attaching structure of an oil cooler, an oil filter and an electric motor (for example, a starter motor) in an engine body of an internal combustion engine, and an oil path structure.
2. Description of Background Art
An internal combustion engine for a vehicle is known which includes an oil cooler, an oil filter and a starter motor and wherein the oil cooler and the oil filter are disposed at a front portion of an engine body, for example, a crankcase. See, for example, Japanese Patent Laid-Open No. 2005-42625.
Since an electric motor (for example, a starter motor) provided in an internal combustion engine for a vehicle generates heat upon being operated, it is preferable to cool the electric motor. However, where the electric motor is disposed behind an apparatus body of the internal combustion engine and cannot face in an advancing direction of the vehicle, an air flow over the vehicle is intercepted by the apparatus body and is less likely to come to the electric motor. Therefore, it is difficult to utilize the air flow to raise the cooling performance of the electric motor.
On the other hand, since an apparatus disposed on the front side of the engine body is likely to be blown by the air flow, where an oil cooler and an oil filter are disposed in a juxtaposed relationship in the advancing direction of the vehicle at the front portion, the oil cooler and the oil filter are cooled by the air flow, and cooling of the oil can be anticipated. However, on an outer face which includes a front face and side faces of the front portion of the engine body, portions which are not occupied by the oil cooler and the oil filter remain without being utilized for an arrangement of any apparatus whose cooling is demanded.
Further, the front portion of the engine body sometimes has a projecting face formed such that an outer face (for example, the front face) of a wall (for example, a front wall) to which the oil cooler or the oil filter is attached projects outwardly (for example, forwardly) in a swollen shape, and a projection which projects outwardly is sometimes provided on the outer face. By utilizing the projecting face or the projection, it is possible to achieve a reduction in the size and weight of an attachment boss to which the oil cooler, oil filter or electric motor is attached while assuring the required rigidity of the attachment boss.
Further, with regard to an oil path for introducing oil having passed through the oil filter and the oil cooler to an oil supply reception section (for example, a main bearing for supporting a crankshaft), in order to reduce the power loss upon driving of the oil pump, it is preferable to reduce the communication resistance to achieve a reduction of the pressure loss of the oil.